refactor(actions): change action type prefix to @@redux-features/

to conform to how everyone else is prefixing their actions

BREAKING CHANGE: the action types have changed (they all started with `REDUX_FEATURES.`, but now

they start with `@@redux-features/` to be consistent with other packages)

Author: jedwards1211

src/actions.js

@@ -2,7 +2,7 @@
 
 import type {Feature, FeatureState, FeatureAction} from './index.js.flow'
 
-export const ACTION_TYPE_PREFIX = 'REDUX_FEATURES.'
+export const ACTION_TYPE_PREFIX = '@@redux-features/'
 export const ADD_FEATURE = ACTION_TYPE_PREFIX + 'ADD_FEATURE'
 export const REPLACE_FEATURE = ACTION_TYPE_PREFIX + 'REPLACE_FEATURE'
 export const LOAD_FEATURE = ACTION_TYPE_PREFIX + 'LOAD_FEATURE'